Search results
Results from the WOW.Com Content Network
Living polymerization: A chain polymerization from which chain transfer and chain termination are absent. Note : In many cases, the rate of chain initiation is fast compared with the rate of chain propagation, so that the number of kinetic-chain carriers is essentially constant throughout the polymerization.
RAFT is a type of living polymerization involving a conventional radical polymerization which is mediated by a RAFT agent. [8] Monomers must be capable of radical polymerization. [9] There are a number of steps in a RAFT polymerization: initiation, pre-equilibrium, re-initiation, main equilibrium, propagation and termination.
Living free radical polymerization is a type of living polymerization where the active polymer chain end is a free radical. Several methods exist. Several methods exist. IUPAC recommends [ 1 ] to use the term " reversible-deactivation radical polymerization " instead of "living free radical polymerization", though the two terms are not synonymous.
Living cationic polymerization is a living polymerization technique involving cationic propagating species. [1] [2] It enables the synthesis of very well defined polymers (low molar mass distribution) and of polymers with unusual architecture such as star polymers and block copolymers and living cationic polymerization is therefore as such of commercial and academic interest.
A special case of chain-growth polymerization leads to living polymerization. Ziegler–Natta polymerization allows considerable control of polymer branching. Polymerization of ethylene. Diverse methods are employed to manipulate the initiation, propagation, and termination rates during chain polymerization.
Living anionic polymerization is a living polymerization technique involving an anionic propagating species. Living anionic polymerization was demonstrated by Szwarc and co workers in 1956. Their initial work was based on the polymerization of styrene and dienes.
There is a mode of polymerization referred to as reversible-deactivation polymerization which is distinct from living polymerization, despite some common features. Living polymerization requires a complete absence of termination reactions, whereas reversible-deactivation polymerization may contain a similar fraction of termination as conventional polymerization with the same concentration of ...
Also known as living radical polymerization, controlled radical polymerization, reversible deactivation radical polymerization (RDRP) relies on completely pure reactions, preventing termination caused by impurities. Because these polymerizations stop only when there is no more monomer, polymerization can continue upon the addition of more monomer.